fix(ses): Improve error messages for invalid module records

[kriskowal]

Just some minor improvements I stumbled into in debugging for #794

[erights]

LGTM

[erights]

If this needs to be unusually high speed code, no change suggested.

Otherwise

Suggested change

	if (staticModuleRecord === null || typeof staticModuleRecord !== 'object') {
	assert.fail(
	assert(staticModuleRecord !== null && typeof staticModuleRecord === 'object',

or

Suggested change

	if (staticModuleRecord === null || typeof staticModuleRecord !== 'object') {
	assert.fail(
	assert.typeof(staticModuleRecord, 'object', ... );
	assert(staticModuleRecord !== null, ...);

or something along those lines.

[kriskowal]

I’ve no reason to believe that the difference would make a perceptible impact on performance, but this is within a performance sensitive region of the Agoric runtime that’s struggling to get close to performance parity with nested evaluate bundles, so I think the code errs on the right side of the balance between succinctness and speed.